An antifoam composition which has been used heretofore to suppress or prevent foam formation in aqueous systems is described in British Pat. No. 1,228,799 to Wacker-Chemie GmbH. This British Patent describes an antifoam composition containing a mixture of an organopolysiloxane, a finely divided inorganic filler and a magnesium, aluminum, calcium, zinc or scandium salt of an aliphatic monobasic carboxylic acid or hydroxycarboxylic acid having from 12 to 22 carbon atoms. Antifoam compositions which contain organosilicon compounds containing hydrocarbonoxy groups are disclosed in U.S. Pat. No. 2,462,999 to Scott. Also, U.S. Pat. No. 2,643,240 to Walton et al discloses an antifoam containing an organopolysiloxane having SiC-bonded monovalent radicals. Also, U.S. Pat. No. 2,416,503 to Trautman et al discloses antifoams which contain organosilicon oxide condensation products composed primarily of silicon atoms linked through oxygen atoms, in which at least one organic radical is attached either directly or through an oxygen atom to each silicon atom.
In comparison to the antifoams described in the above cited patents, the antifoams which are the subject of this invention are easier to prepare than the organopolysiloxanes having an average of two monovalent hydrocarbon radicals linked to each silicon atom and surprisingly the antifoams of this invention are just as effective as the diorganopolysiloxanes used heretofore. Moreover, the antifoams of this invention are more stable for longer periods of time without any apparent separation. Furthermore, the antifoams of this invention are more effective and can be easily combined with organic materials which are used as emulsifiers and/or alcohols and are more readily dispersed in an aqueous system.
Therefore, it is an object of this invention to provide an antifoam which is more effective in suppressing and/or preventing foam formation. Another object of this invention is to provide an antifoam which is stable over a longer period of time. Still another object of this invention is to provide an antifoam which is readily combined with emulsifiers and is easily dispersed in aqueous systems.